This week’s flooding in Vermont, in which torrential rains wreaked havoc far from rivers or coasts, is evidence of a particularly dangerous climate threat: catastrophic flooding can increasingly happen anywhere, almost without warning.
And the United States, experts warn, is nowhere near ready for that threat.
The idea that wherever it can rain, it can flood, is not new. But rising temperatures make the problem worse: they make the air hold more moisture, leading to more intense and sudden rainfall, seemingly out of nowhere. And the implications of that shift are enormous.
“It’s becoming increasingly difficult to adapt to these changing conditions,” said Rachel Cleetus, policy director for the climate and energy program at the Union of Concerned Scientists. “It’s just everywhere, all the time.”
The federal government is already struggling to prepare American communities for severe flooding, funding better sewers and pumps, building levees and seawalls, and raising roads and other basic infrastructure. As seas rise and storms get worse, the most flood-prone parts of the country — places like New Orleans, Miami, Houston, Charleston, or even parts of New York City — could easily eat up the entire government budget for climate resilience, without adding to the problems. to solve. problem for each of them.
Federal flood maps, which governments use as a guide to where to build housing and infrastructure, should be updated regularly. But often they fail to capitalize on the full risk – the result of a lack of resources, but also sometimes pushback from local officials who don’t want new frontiers of development.
And as the Vermont floods demonstrate, the government can’t just focus its resilience efforts on the obvious areas, near coasts or rivers.
But the country lacks a comprehensive, up-to-date, national precipitation database that could help inform homeowners, communities and the government about the increasing risks of heavy rainfall.
In Vermont, the actual number of homes threatened by flooding is is three times what federal flood maps show, according to data from the First Street Foundation, a New York-based nonprofit research group.
That so-called “hidden risk” is also alarmingly high in other parts of the country. In Utah, the number of properties at risk when rainfall is taken into account is eight times what appears on federal flood maps, according to First Street. In Pennsylvania, the risk is five and a half times that; in Montana, four times as many. About 16 million properties are at risk nationwide, compared to 7.5 million in federally designated flood zones.
The result is severe flooding in what may seem like unexpected places, such as Vermont. Last summer, rains closed off parts of Yellowstone National Park, forcing visitors to evacuate. In March, heavy rain triggered federal disaster declarations in six counties in Nevada, the driest state in the country.
The Vermont floods highlight the need to spend more on flood event modeling and planning, said Mathew Sanders, who leads state efforts for the Pew Charitable Trusts. “You have to watch how the water is going to flow,” he said. “We need to rethink what the most strategic interventions will be.”
All that water often brings tragedy in places least able to handle it.
Last year, a deluge of rain caused flash floods that poured through the hollows of eastern Kentucky. The force of the water destroyed some houses, mutilated trucks and clogged the remaining buildings with mud and debris. More than 35 people died.
The communities scattered across the Appalachian Mountains are familiar with flooding, with water flowing from the creeks that flow through the area. But the ferocity of that flood left old families stunned. “We went from being in bed to homeless in less than two hours,” said Gary Moore, whose home just outside Fleming-Neon, Kentucky, was destroyed in the days following the flood.
The flooding exacerbated by climate change was also exacerbated by the lingering effects of coal mining, as the industry that once powered communities retreated, leaving behind stripped hills and mountains whose tops had been blown away. The loss of trees worsened the rate and volume of storm runoff.
In Houston, deadly and destructive flooding has long been a familiar threat, so much so that the worst storms have become shorthand for marking time: Tropical Storm Beta (2020), Tropical Storm Imelda (2019), Hurricane Harvey (2017) and the Flood Tax Day (2016).
But as many as half of homes breached by floodwaters in recent years were outside official flood risk zones. An analysis by the Harris County Flood Control District found that 68 percent of homes flooded during Hurricane Harvey were outside the 100-year-old floodplain, due to rising water in the creeks and swamps flowing through the area. flowed.
In Summerville, Georgia, a town of some 4,400 in the ridges in the northwest corner of the state, a flash flood last year inundated homes and businesses following a deluge caused by the remnants of Tropical Storm Claudette. Much of Summerville falls outside the 100-year floodplain, and the devastation and resulting cleanup overwhelmed the city.
Flooding has also become a source of frustration and pain in Horry County, SC, a coastal area that includes the resort town of Myrtle Beach. April O’Leary, a resident who founded a group called Horry County Rising, said at a 2021 hearing with federal disaster response officials that nearly half of the homes flooding in the county were outside the designated flood zone.
“There really is no such thing as recovery when you flood,” Ms O’Leary told officials. “Financially you never fully recover and families live in constant fear of flooding.”
As the threat of flooding and other climate shocks grows, the federal government has allocated more money to climate resilience projects. The 2021 infrastructure bill provided about $50 billion for such projects, the largest infusion in U.S. history.
But that funding is still far below the need. This spring, the Federal Emergency Management Agency said it had received $5.6 billion in applications for two of its major disaster preparedness programs — nearly twice as much as was available.
Anna Weber, a senior policy analyst at the Natural Resources Defense Council who specializes in flood risk, said the government should spend more money on the most economically vulnerable communities – those places least able to afford resilience projects on their own.
But the scale required is also an opportunity to fix old mistakes, said Amy Chester, general manager of Rebuild by Design, a New York-based nonprofit that helps communities prepare for and recover from disasters. She said cities and towns can rethink how they build, return the land built on rivers, streams and wetlands to nature, and create new parks or other landscapes to hold rain.
In that sense, she said, adaptation to climate change is an opportunity. “When else,” Mrs. Chester asked, “can you rethink how you want to live?”
